Using the facultative anaerobic bacterium Rhodopseudomonas sphaeroides we are studying the induction and steady-state synthesis of the intracytoplasmic membrane. Physiologic, biochemical, genetic and physiochemical approaches are being employed in order that we might establish the following: 1) The role of the cell membrane and outer membrane on intracytoplasmic membrane synthesis and control. 2) The effect of light and oxygen on the synthesis of the intracytoplasmic membrane. 3) The regulation of phospholipid synthesis and its relationship to intracytoplasmic membrane synthesis. 4) The nature and physiochemical properties of intracytoplasmic membrane proteins. 5) The relationship and organization of the proteins and lipids of the intracytoplasmic membrane to one another. 6) The sequence of events and their control in intracytoplasmic membrane synthesis.